<!doctype html>
<html lang="zh-cn">
<head>
	<meta charset="UTF-8">
	<title>火车运行时刻</title>
</head>
<body>
	<script>
		var num = 17.5
		, 	str = ""
		, 	total = num*12
		, 	hour = 5
		,	second = 30;
		for(var i=0;i<=total;i++){
			var seconds = second+i*5;
			if(seconds>=60){
				second = 0;
				seconds = "00";
				total = total - i;
				i = 0;
				hour++;
			}
			if(seconds == 5){
				seconds = "05";
			}
			str += hour+":"+seconds+" 发车<br>";
		}
		document.write(str);
		
		
	</script>
</body>
</html>